Question:
Why do I get Red-Eye in my flash pictures and what can I do about it?

Answer:
In low-light situations the pupils of humans and animals dilate in order to see more clearly.
You may have seen the glowing eyes of a deer in your headlights at night. If the pupils are
dilated and the flash on the camera is positioned close to the lens axis, the light will illuminate
the retina in the back of the eye, and it is this illumination that is red-eye. The human retina is
red. Nocturnal animals such as dogs, cats, raccoons, and deer may have yellow, green, or blue retinas.
This is because nocturnal animals have a reflective layer on their retinas called the tapetum lucidum
that enables them to see more clearly in very dark environments. The color of the reflection in the
same animal may vary due to the angle the eyes are facing the flash.

Camera designers have different ways to reduce red-eye. Moving the flash away from the lens axis can
eliminate red eye. However, a compact camera may not be large enough to move the flash far enough
off-axis. The Red-Eye Reduction feature found in cameras can reduce red-eye by firing a rapid series
of pre-flashes, the subject's pupils will close down so that the area illuminated in the eye is
smaller and off-axis with the lens. Once the camera has fired its pre-flashes it then takes the flash
picture. The red-eye is still there, but can't be seen by the lens because it is off to the side behind
the pupil. Another technique is to raise the flash higher above the lens axis, as is done in digital SLRs,
or use an accessory flash in the camera's hot shoe.

Even with all of these measures, red-eye may occur. OLYMPUS Master and OLYMPUS Studio software have a
Red-Eye correction tool in the Edit Palette.

The AUTO and One-Click options search for human red-eye and correct it. The Manual option allows selection of the color and the ability to select the area to be corrected. In Olympus software it colors in the red-eye with a deep gray and adds a catchlight.